Laser Through-Hole Forming in Glass Substrates
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Solution Overview
Problem
Existing through-hole forming methods using laser irradiation often result in significant deviations from the target shape, leading to collapse or irregularities such as protrusions or narrow parts in the formed holes.
Innovation Solution
A through-hole forming method and apparatus that condenses and irradiates a laser beam onto an insulation substrate through a lens with a converging half angle θ calculated using the expression (d/2)/f = tan θ, where 0.16 ≤ sin θ ≤ 0.22, to suppress shape collapse and achieve a more symmetrical, linearly tapered through-hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser beam is irradiated onto a glass substrate to form a through-hole, then a through-hole can be formed that passes through the substrate, but the shape of the formed through-hole significantly deviates from the target shape
Solution Approach 1:
The patent applies parameter changes by optimizing the converging half angle θ of the laser beam to a specific range (0.16 ≤ sin θ ≤ 0.22) and adjusting the laser beam diameter d relative to the focal length f of the lens. This specific parameter configuration prevents shape collapse and maintains through-hole shape accuracy, resolving the contradiction between manufacturing precision and reliability.
Solution Approach 2:
The patent employs preliminary anti-action by pre-calculating and controlling the laser beam parameters (converging half angle θ and beam diameter d) before irradiation to prevent shape collapse. By setting the medium between the lens and substrate to air and configuring the optical system in advance, the method prevents harmful effects before they occur, ensuring both shape accuracy and reliability.
2Productivity
If the converging half angle θ is increased to improve processing speed, then productivity increases, but the through-hole shape deviation worsens
Solution Approach 1:
The patent resolves this contradiction by identifying an optimal parameter range for the converging half angle θ where 0.16 ≤ sin θ ≤ 0.22. This specific parameter setting allows for sufficiently fast processing while maintaining excellent shape accuracy, preventing both shape collapse and excessive taper. The beam diameter d and focal length f are also optimized together to achieve the desired balance between productivity and precision.
3Productivity
If the laser beam diameter d is increased to reduce the number of passes, then productivity improves, but the energy density decreases leading to poor hole quality
Solution Approach 1:
The patent resolves this contradiction by optimizing the relationship between beam diameter d and focal length f, along with the converging half angle θ. By setting appropriate parameters within the specified ranges, the method achieves effective single-pass or multi-pass processing while maintaining high energy density at the focal point, ensuring both productivity and through-hole quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively regulates the shape of the through-hole, preventing collapse and ensuring a consistent ratio of diameters within the hole, which is crucial for forming defect-free through-electrodes and interposers.
Implementation Method 1
by condensing and irradiating a laser beam onto an insulation substrate through a lens
Implementation Method 2
irradiating a laser beam onto a glass substrate
Implementation Method 3
irradiating a laser beam onto a glass substrate
Implementation Method 4
forming a through-hole that passes through the glass substrate
Data Source
AI summary
Disclosed is a through-hole forming method including a process of forming, by condensing and irradiating a laser beam onto an insulation substrate through a lens, a through-hole that passes through the insulation substrate in a thickness direction of the insulation substrate. A medium between the lens and the insulation substrate is air. A converging half angle θ that is calculated from a focal length f of the lens and a beam diameter d of the laser beam that enters the lens by using expression (1) satisfies expression (2):(d/2)/f=tan θ (1), and0.16≤sin θ≤0.22 (2).